If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #3429
Joined: Sun Nov 21 2010, 02:04AM
Location: Minnesota, USA
Posts: 288
radhoo wrote ...
@Xray: actually there is an easy way around that, probably you've all seen self-powered little radios using just a few components. would love to see your project, but since it was long ago, you probably don't have any pics.
Yeah, that was a loooooooooooooooooooooooong time ago, indeed! Sorry...
Registered Member #1792
Joined: Fri Oct 31 2008, 08:12PM
Location: University of California
Posts: 527
radhoo wrote ...
Thanks for the feedback, guys, I was about to think you're all away on some exotic holidays, drinking cocktails and having fun
I have been swamped with work of late and not off on holiday, though I still manage to drink a few cocktails and have fun
wrote ... @haxor5354: all electromagnetic waves (radio, light, X-rays, etc.) obey the inverse-square law. so yes, distance can be a problem.
This is operating with near field magnetic coupling rather than radiation I believe so you're actually worse off, the magnetic field from a current loop tends to decay with 1/r^3 rather than 1/r^2. Maybe take some readings of voltage on your load at measured distances, though I'd use a high power resistor rather than the lamp as the resistance of an incandescent bulb can change dramatically as it heats up and cools down.
Registered Member #1938
Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 699
Mattski wrote ...
This is operating with near field magnetic coupling rather than radiation I believe so you're actually worse off, the magnetic field from a current loop tends to decay with 1/r^3 rather than 1/r^2. Maybe take some readings of voltage on your load at measured distances, though I'd use a high power resistor rather than the lamp as the resistance of an incandescent bulb can change dramatically as it heats up and cools down.
A very good suggestion, so I will do this as soon as I get the next time slot for this experiment. Too many things to do, too little time.
Registered Member #3637
Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068
Increase the number of primary turns. It decreases current draw from what I've seen. I've gotten draw as low as 1 amp with around 5 + 5 turns on my mini ZVS wireless transmitter.... I assume if you add even more you'd get even lower draw. You'd have to experiment though!
Registered Member #1938
Joined: Sun Jan 25 2009, 12:44PM
Location: Romania
Posts: 699
Yes, that will probably work, but I am open to other designs as well, as the royer oscillator might not function properly for lower voltages, unless I change the mosfets for BJTs.
On the other hand I need to go down scale, so the diameter of the coil needs to be reduced as well.
From what I understand, the diameter of the coil has a DIRECT impact on the transmission distance. How to overcome that? Any ideas?
Registered Member #3637
Joined: Fri Jan 21 2011, 11:07PM
Location: Buffalo, NY
Posts: 1068
I think you'd have to use some chip to generate "negative" resistance if you're using a royer at lower voltages... something like what's on page 14 on here;
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Wireless power transmitter
